912 fuel pump shelf life

Technically I would imagine that a pump stored in benign conditions on the shelf is unlikely to degrade very much. Most of the degradation will occur when it is operated on the engine where it is subject to heat, the diaphragm is flexed and is in contact with petroleum.

Personally I would only start the clock running from when it has been installed AND has been operated with the engine running. If it was just attached to an engine that has not had fuel run through it then I would treat it the same as on the shelf.

The Mechanical fuel pumps have a "Service Life" of 5 years and no "Shelf Life" because it is not made of rubber. 

Rotax Service Letter SL-912-022R2, section 3.1.2) Shelf life states the following:

The shelf life is the length of time a part can be stored before being installed on an aircraft (Not to be confused with SERVICE LIFE). SERVICE LIFE: Service life is that period from installation to retirement.

3.1.3) ROTAX® genuine spare parts

The shelf life on genuine spare parts does mainly affects parts made of rubber (like hoses, O-rings, oil seals,....). Rubber parts sent from BRP-Rotax GmbH & Co KG have a minimum of 48 months of shelf life beyond the invoice date. For all other parts general storage requirements apply

Reference: https://legacy.rotaxowner.com/si_tb_info/serviceletter/sl-914-020-r2.pdf

Thanks for the elaborate reply.

As far as I know the fuel pump contains some "rubber" parts. See picture. Doesn't it implies that it  has a shelf life? If so, is it 48 months similar to other Rotax jenuine rubber spare parts?

This is the list of parts that have a Shelf Life of 48 months (They are also part of the 5-year rubber replacement requirements)

• Venting hose of the carburetors
• The diaphragm on both carburetors
• Carburetor sockets 
• All rubber hoses of the cooling system 
• All rubber hoses of the fuel system See SI-912-022, latest issue
• All rubber hoses of the lubrication system which are part of the engine supply volume and if they are not in the maintenance schedule of the aircraft manufacturer •
• Connecting hose of the air intake system •
• Venting hose of the fuel pump •
• V-belt • Rubber plate (under expansion Tank) •
• O-Ring 44x2 (between carburetor socket and intake manifold)

The fuel pump has a 5-year service life (no shelf life). Once the fuel pump gets installed on the engine, an entry is placed into the maintenance log book, and the clock starts then (now considered "in-service"). If there is no installation date in the maintenance log book, then you would have no choice but to go by the manufactured date of the fuel pump.

It is the same as the TBO on the engine 2000 hours or 15 years (whichever comes first). 15 years is not the "shelf life" of the engine, it is the service life of the engine. An engine is not going to need an overhaul if it is sitting in a box on the shelf for 15 years, however, it will require an inspection. 

Rotax states the following:

The engine is preserved at BRP-Rotax thus guaranteeing proper protection against corrosion damage for at least 12 months after the date of delivery from BRP-Rotax. This warranty is subject to the following conditions: 

• The engine must be stored in the GENUINE ROTAX® packing as supplied by BRPRotax.
• The covers on various openings must not be removed
• The engine must be stored in a suitable place (at min. -40 °C/-40 °F and max. +80 °C/ 176 °F) 
• The bag (blue) surrounding the engine must not be damaged or removed, as it protects the engine from corrosion and oxidation If the engine is stored for a period longer than 12 months (or it is not stored in the GENUINE ROTAX® packing) then maintenance tasks must be carried out every 3 months as per the currently valid Maintenance Manual Line.

References: 

https://www.rotax-owner.com/pdf/IM_912_Series_Ed3_R0.pdf

https://www.rotax-owner.com/pdf/MML_912-Series_Ed4-Rev1.pdf

I am replacing the #893115 Fuel Pump with a new #893115 Fuel Pump.  I will replace the associated O-ring with new.  My question is:  Assuming it is not damaged, do I need to replace the old #950228 Isolating Gasket as well??  Thanks!